US7928339B2 - Device for gaseous plasma sterilization - Google Patents

Device for gaseous plasma sterilization Download PDF

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Publication number
US7928339B2
US7928339B2 US11/722,722 US72272205A US7928339B2 US 7928339 B2 US7928339 B2 US 7928339B2 US 72272205 A US72272205 A US 72272205A US 7928339 B2 US7928339 B2 US 7928339B2
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United States
Prior art keywords
magnetron
diode
joined
peak
power
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Expired - Fee Related, expires
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US11/722,722
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English (en)
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US20090035196A1 (en
Inventor
Pascal Regere
André Ricard
Sarah Cousty
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Societe pour la Conception des Applications des Techniques Electroniques SAS
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Societe pour la Conception des Applications des Techniques Electroniques SAS
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Assigned to SOCIETE POUR LA CONCEPTION DES APPLICATIONS DES TECHNIQUES ELECTRONIQUES-SATELEC reassignment SOCIETE POUR LA CONCEPTION DES APPLICATIONS DES TECHNIQUES ELECTRONIQUES-SATELEC ASSIGNMENT OF ASSIGNORS INTEREST (SEE DOCUMENT FOR DETAILS). Assignors: COUSTY, SARAH, REGERE, PASCAL, RICARD, ANDRE
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    • H—ELECTRICITY
    • H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
    • H05H—PLASMA TECHNIQUE; PRODUCTION OF ACCELERATED ELECTRICALLY-CHARGED PARTICLES OR OF NEUTRONS; PRODUCTION OR ACCELERATION OF NEUTRAL MOLECULAR OR ATOMIC BEAMS
    • H05H1/00—Generating plasma; Handling plasma
    • H05H1/24—Generating plasma
    • H05H1/46—Generating plasma using applied electromagnetic fields, e.g. high frequency or microwave energy
    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61L—METHODS OR APPARATUS FOR STERILISING MATERIALS OR OBJECTS IN GENERAL; DISINFECTION, STERILISATION OR DEODORISATION OF AIR; CHEMICAL ASPECTS OF BANDAGES, DRESSINGS, ABSORBENT PADS OR SURGICAL ARTICLES; MATERIALS FOR BANDAGES, DRESSINGS, ABSORBENT PADS OR SURGICAL ARTICLES
    • A61L2/00—Methods or apparatus for disinfecting or sterilising materials or objects other than foodstuffs or contact lenses; Accessories therefor
    • A61L2/02—Methods or apparatus for disinfecting or sterilising materials or objects other than foodstuffs or contact lenses; Accessories therefor using physical phenomena
    • A61L2/14—Plasma, i.e. ionised gases
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01J—ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS
    • H01J37/00—Discharge tubes with provision for introducing objects or material to be exposed to the discharge, e.g. for the purpose of examination or processing thereof
    • H01J37/32—Gas-filled discharge tubes
    • H—ELECTRICITY
    • H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
    • H05B—ELECTRIC HEATING; ELECTRIC LIGHT SOURCES NOT OTHERWISE PROVIDED FOR; CIRCUIT ARRANGEMENTS FOR ELECTRIC LIGHT SOURCES, IN GENERAL
    • H05B6/00—Heating by electric, magnetic or electromagnetic fields
    • H05B6/64—Heating using microwaves
    • H05B6/66—Circuits
    • H05B6/68—Circuits for monitoring or control
    • H—ELECTRICITY
    • H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
    • H05H—PLASMA TECHNIQUE; PRODUCTION OF ACCELERATED ELECTRICALLY-CHARGED PARTICLES OR OF NEUTRONS; PRODUCTION OR ACCELERATION OF NEUTRAL MOLECULAR OR ATOMIC BEAMS
    • H05H2242/00—Auxiliary systems
    • H05H2242/20—Power circuits
    • H05H2242/24—Radiofrequency or microwave generators
    • H—ELECTRICITY
    • H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
    • H05H—PLASMA TECHNIQUE; PRODUCTION OF ACCELERATED ELECTRICALLY-CHARGED PARTICLES OR OF NEUTRONS; PRODUCTION OR ACCELERATION OF NEUTRAL MOLECULAR OR ATOMIC BEAMS
    • H05H2245/00—Applications of plasma devices
    • H05H2245/30—Medical applications
    • H05H2245/36—Sterilisation of objects, liquids, volumes or surfaces

Definitions

  • the present invention pertains to a sterilization device for medical instruments in particular, of the type which uses a gas plasma.
  • a gas which does not itself have bactericidal properties, which is subjected to a sufficiently high electric field to cause its ionisation and the separation of its molecules.
  • the gas produced downstream of the plasma called “post-discharge” gas has sterilizing properties. This gas enters a treatment chamber where it exerts its bactericidal action on the instruments to be sterilized.
  • the high frequency current technique has the disadvantage of using electrodes subject to wear and with which it is not possible to obtain good stability of the device so that the device needs to be permanently adjusted.
  • the microwave technique does not have these drawbacks but is nonetheless not free of some constraints, in particular regarding lifetime and the frequency stability of the magnetron generating the microwaves.
  • a microwave source consists of a magnetron delivering its energy within a waveguide which transmits this energy to an energy-absorbing cavity resonator in which it is desired to conduct a certain task.
  • This cavity therefore absorbs part of the emitted energy, and part of the remaining energy is reflected towards the magnetron.
  • the lifetime of the magnetron is directly related to this reflected power. If it is too high, it generates a rise in temperature of the magnetron which may lead to its final breakdown.
  • the magnetron should have a long lifetime compatible with the lifetimes generally accepted in medical industry sectors.
  • the power absorbed in the resonant cavity is essentially variable since its depends upon the mass of instruments to be sterilized. Therefore it is important that the magnetron should be able to operate with a reflected power corresponding to its total power (which corresponds to an almost empty cavity resonator) and for a large number of times without undergoing irreversible damage.
  • the purpose of the present invention is to propose a microwave generator intended for the production of a gas plasma, which remedies these disadvantages by ensuring excellent operating stability and an optimal lifetime of its magnetron.
  • a further subject of the invention is a device for producing a gas plasma by ionising a gas using a microwave source of determined nominal power, comprising a magnetron receiving its electric energy from a supply circuit, characterized in that the power delivered to the magnetron by the supply circuit is at least equal to one quarter of the nominal power of the magnetron. Preferably, this power lies between one tenth and one quarter of the magnetron's nominal power.
  • the power delivered to the magnetron by the supply circuit is no more than one quarter of the product of the magnetron's nominal power multiplied by the reflection coefficient of the magnetron.
  • the inventive device may comprise means able to limit the power delivered to the magnetron, which are such that its temperature does not exceed 80° C.
  • the present invention is of particular interest at production cost level, in that it can have recourse to circuits available on the household products market and which, since they are mass produced, have a particularly competitive cost price.
  • One disadvantage of such circuits when it is desired to use the same in areas such as the medical sterilization sector, is that firstly they have a power in the order of 800 W whereas for sterilization the power which can be absorbed by the treatment cavity is in the order of only 100 W, and secondly their reliability is low.
  • magnetrons for start-up, require a peak voltage of relatively high value in the order of 3 to 4 kv.
  • the power supplied to the magnetron is limited, which will limit the energy reflected towards it, and this limitation is achieved without reducing the required starting load.
  • One manner of particular interest for reducing the electric power supplied to the magnetron, whilst maintaining said peak voltage at a sufficient value, is to use a voltage doubler having a diode and a capacitor arranged in series at the terminals of the secondary winding and to use a capacitor of sufficiently low value to cause the voltage to drop. Under these conditions it was found that the power supplied to the magnetron is sufficiently reduced to ensure its sufficient reliability whilst preserving its starting peak load.
  • SWR Standing Wave Ratio
  • the energy able to be thermally dissipated by a magnetron is proportional to its power. Therefore, bearing in mind that the mean SWR for a magnetron is in the order of 4, the corresponding reflection coefficient r is 0.6, which means that a magnetron having a nominal power of 800 watts will have a permissible reflected power of 480 watts, whereas this same value for a magnetron having a nominal power of 300 watts will only be 180 watts.
  • P n being the nominal power of the magnetron.
  • FIG. 1 is a schematic view of an inventive device
  • FIG. 2 is a curve showing the variation in power delivered to the magnetron in relation to the capacity value of the capacitor in the supply means.
  • FIG. 3 is a curve showing the variation in voltage in relation to time at the terminals of the magnetron in a device of the type shown FIG. 1 ,
  • FIG. 4 is a schematic view of a variant of embodiment of the invention.
  • FIG. 1 shows a supply device able to supply the magnetron with the energy it needs to produce a gas plasma.
  • This gas plasma is particularly intended, via its post-discharge gas, to ensure a sterilizing function.
  • the supply essentially consists of a voltage step-up supply transformer 1 , having a ratio of approximately 10, so that with a peak-to-peak supply voltage of 220 V, the peak-to-peak voltage at its secondary winding will be approximately 2200 V.
  • a capacitor C and a diode D Arranged in series in the secondary circuit 1 b are a capacitor C and a diode D between whose terminals A and B a magnetron 7 is connected. This magnetron is joined by a waveguide 8 to a cavity resonator 9
  • the diode D and capacitor C form a voltage doubler making it possible to multiply by 2 the output voltage of transformer 1 , since capacitor C becomes charged during positive alternation and when alternation becomes negative the voltage of the capacitor is added to its voltage value.
  • a curve was plotted showing the variation in power P supplied by the supply circuit to the magnetron 7 in relation to the value of the capacitor C. It is therefore found in FIG. 2 that the power P decreases with the value of the capacitor. Therefore for a capacitor C of 0.9 ⁇ F, the value conventionally used for the supply of household microwave ovens, the delivered power is approximately 900 W, whereas if the value of capacitor C is reduced to 0.1 ⁇ F, this power drops to 100 W which is a value corresponding to the power used in the particular area of gas plasma production for sterilization purposes using its post-discharge gas. This is of particular interest since, even if the power is fully reflected, its value will be below the value of the permissible return power, which for a magnetron of 800 W nominal power is 480 W.
  • FIG. 3 a curve is shown FIG. 3 expressing the variation in voltage at terminals A and B of the magnetron supply. It is found that the peak voltage thereupon at the start of alternation is well maintained, making it possible to provide the magnetron with a proper starting load.
  • FIG. 4 It is also possible, according to the invention, as is shown FIG. 4 to provide a double alternating supply to the magnetron.
  • a loop is provided comprising two diodes in series, namely a first diode D 1 and a second diode D 2 , the output of the first being joined to the input of the second, and two capacitors C 1 and C 2 .
  • An output terminal E of transformer 1 is joined between the two capacitors C 1 and C 2 and the other output terminal F is joined via a resistance R to the input of diode D 2 .
  • the magnetron is supplied between the input terminal A′ of the first diode D 1 and the output terminal B′ of the second diode D 2 .
  • Said assembly accumulates the two voltage doublers and the voltage delivered between terminals A′ and B′ is the sum of the voltages at the terminals of capacitors C 1 and C 2 .
  • capacitor C 1 charges via diode D 1 .
  • alternation becomes negative capacitor C 2 charges via diode D 2 .

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  • Physics & Mathematics (AREA)
  • Engineering & Computer Science (AREA)
  • Plasma & Fusion (AREA)
  • Electromagnetism (AREA)
  • Spectroscopy & Molecular Physics (AREA)
  • Health & Medical Sciences (AREA)
  • Public Health (AREA)
  • General Health & Medical Sciences (AREA)
  • Animal Behavior & Ethology (AREA)
  • Veterinary Medicine (AREA)
  • Life Sciences & Earth Sciences (AREA)
  • Epidemiology (AREA)
  • Chemical & Material Sciences (AREA)
  • Analytical Chemistry (AREA)
  • Apparatus For Disinfection Or Sterilisation (AREA)
  • Plasma Technology (AREA)
  • Microwave Tubes (AREA)
  • Rectifiers (AREA)
US11/722,722 2004-12-23 2005-12-21 Device for gaseous plasma sterilization Expired - Fee Related US7928339B2 (en)

Applications Claiming Priority (3)

Application Number Priority Date Filing Date Title
FR0413818A FR2880235B1 (fr) 2004-12-23 2004-12-23 Dispositif de sterilisation par plasma gazeux
FR0413818 2004-12-23
PCT/FR2005/003223 WO2006070107A1 (fr) 2004-12-23 2005-12-21 Dispositif de sterilisation par plasma gazeux

Publications (2)

Publication Number Publication Date
US20090035196A1 US20090035196A1 (en) 2009-02-05
US7928339B2 true US7928339B2 (en) 2011-04-19

Family

ID=34952664

Family Applications (1)

Application Number Title Priority Date Filing Date
US11/722,722 Expired - Fee Related US7928339B2 (en) 2004-12-23 2005-12-21 Device for gaseous plasma sterilization

Country Status (16)

Country Link
US (1) US7928339B2 (fr)
EP (1) EP1829438B1 (fr)
JP (1) JP5107052B2 (fr)
KR (1) KR20070107681A (fr)
CN (1) CN101147431B (fr)
AU (1) AU2005321172B2 (fr)
BR (1) BRPI0519220B1 (fr)
CA (1) CA2594004C (fr)
DK (1) DK1829438T3 (fr)
ES (1) ES2532261T3 (fr)
FR (1) FR2880235B1 (fr)
HK (1) HK1117327A1 (fr)
IL (1) IL183864A (fr)
RU (1) RU2388195C2 (fr)
TW (1) TWI389710B (fr)
WO (1) WO2006070107A1 (fr)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US10763814B2 (en) 2016-08-09 2020-09-01 John Bean Technologies Corporation Radio frequency processing apparatus and method

Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN113426020B (zh) * 2021-05-25 2022-09-09 深圳市飞立电器科技有限公司 一种接触式等离子消毒仪

Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4317976A (en) 1978-06-28 1982-03-02 Tokyo Shibaura Denki Kabushiki Kaisha High frequency heating apparatus
US4849595A (en) 1985-06-17 1989-07-18 Robertshaw Controls Company Electrically operated control device and system for a microwave oven
JPH06104079A (ja) 1992-09-16 1994-04-15 Sanyo Electric Co Ltd 高周波加熱装置
US5325020A (en) 1990-09-28 1994-06-28 Abtox, Inc. Circular waveguide plasma microwave sterilizer apparatus
US6445596B1 (en) 1999-06-15 2002-09-03 Matsushita Electric Industrial Co., Ltd. Magnetron drive power supply

Family Cites Families (10)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS491523Y1 (fr) * 1969-05-22 1974-01-16
JPH0635662B2 (ja) * 1985-09-19 1994-05-11 松下電器産業株式会社 プラズマ装置
JPS62208378A (ja) * 1986-02-28 1987-09-12 東洋製罐株式会社 デユアル・オ−ブナブル容器
GB8613567D0 (en) * 1986-06-04 1986-07-09 Electrolux Ab Power supply circuits
KR910006172B1 (ko) * 1987-07-06 1991-08-16 마쯔시다덴기산교 가부시기가이샤 전기기기의 제어장치
JPH02279160A (ja) * 1989-03-08 1990-11-15 Abtox Inc プラズマ滅菌方法及び滅菌装置
JPH0594899A (ja) * 1991-10-02 1993-04-16 Nippon Steel Corp プラズマ処理装置
JPH05144381A (ja) * 1991-11-20 1993-06-11 Hitachi Ltd マグネトロン応用装置
JP5138131B2 (ja) * 2001-03-28 2013-02-06 忠弘 大見 マイクロ波プラズマプロセス装置及びプラズマプロセス制御方法
KR100428511B1 (ko) * 2002-05-27 2004-04-29 삼성전자주식회사 전자레인지 및 그 제어 방법

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4317976A (en) 1978-06-28 1982-03-02 Tokyo Shibaura Denki Kabushiki Kaisha High frequency heating apparatus
US4849595A (en) 1985-06-17 1989-07-18 Robertshaw Controls Company Electrically operated control device and system for a microwave oven
US5325020A (en) 1990-09-28 1994-06-28 Abtox, Inc. Circular waveguide plasma microwave sterilizer apparatus
JPH06104079A (ja) 1992-09-16 1994-04-15 Sanyo Electric Co Ltd 高周波加熱装置
US6445596B1 (en) 1999-06-15 2002-09-03 Matsushita Electric Industrial Co., Ltd. Magnetron drive power supply

Non-Patent Citations (1)

* Cited by examiner, † Cited by third party
Title
Patent Abstract of Japan vol. 018, No. 372 (E-1577)m Jul. 13, 1994.

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US10763814B2 (en) 2016-08-09 2020-09-01 John Bean Technologies Corporation Radio frequency processing apparatus and method
US11489507B2 (en) 2016-08-09 2022-11-01 John Bean Technologies Corporation Radio frequency processing apparatus and method

Also Published As

Publication number Publication date
HK1117327A1 (en) 2009-01-09
EP1829438B1 (fr) 2014-12-17
JP5107052B2 (ja) 2012-12-26
IL183864A (en) 2013-11-28
EP1829438A1 (fr) 2007-09-05
CA2594004A1 (fr) 2006-07-06
AU2005321172B2 (en) 2011-04-28
WO2006070107A1 (fr) 2006-07-06
ES2532261T3 (es) 2015-03-25
IL183864A0 (en) 2007-10-31
FR2880235A1 (fr) 2006-06-30
DK1829438T3 (en) 2015-03-02
KR20070107681A (ko) 2007-11-07
RU2388195C2 (ru) 2010-04-27
CA2594004C (fr) 2017-03-14
CN101147431A (zh) 2008-03-19
CN101147431B (zh) 2011-09-14
FR2880235B1 (fr) 2007-03-30
WO2006070107A8 (fr) 2007-08-16
BRPI0519220A2 (pt) 2009-01-06
RU2007123086A (ru) 2009-01-27
JP2008525952A (ja) 2008-07-17
TWI389710B (zh) 2013-03-21
US20090035196A1 (en) 2009-02-05
TW200628177A (en) 2006-08-16
AU2005321172A1 (en) 2006-07-06
BRPI0519220B1 (pt) 2017-12-19

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